As is known in the art of computer animation and modeling, the DECface.TM. product developed by Digital Equipment Corporation provides a computer generated talking synthetic face. The DECface.TM. computer generated talking synthetic face is a visual complement to the DECtalk.TM. product, a speech synthesizer also developed by Digital Equipment Corporation. By combining the audio functionality of a speech synthesizer with the graphical functionality of a computer generated talking synthetic face, a variety of engaging user interfaces can be provided. Examples include internet-based agents capable of seeking and retrieving documents on the world-wide web, avatars for chat applications, and front-end interfaces for kiosks.
A technique for adaptively synchronizing an audio signal of a speech synthesizer with a facial image being displayed is described by Waters et al. in U.S. Pat. No. 5,657,426, entitled Method and Apparatus for Producing Audio-Visual Synthetic Speech, issued Aug. 12, 1997, assigned to the assignee of the present application, and hereby incorporated herein by reference. Waters et al. disclose a speech synthesizer that generates fundamental speech units called phonemes, which are converted into audio signals. The phonemes are also converted into visual facial configurations called visemes (i.e., distinct mouth postures). The visemes are grouped into sequences of mouth gestures approximating the gestures of speech. The sequences of mouth gestures are then synchronized to the corresponding audio signals.
While Waters et al. provide a technique for synchronizing audio speech with visual mouth gestures, other gestures, such as those associated with facial or other body movements, are not addressed. That is, Waters et al. do not address providing other gestures which typically accompany mouth gestures during speech.
Also, Waters et al. do not address providing gestures which are not associated with speech. That is, Waters et al. do not address providing other gestures, such as those associated with facial or other body movements, which by themselves are often a means of expression or communication.
Some attempts have been made to provide animated facial and other body gestures. For example, animated facial gestures made up of individual facial components have been provided in accordance with the teachings of Parke, F. and Waters, K., in Computer Facial Animation, A K Peters, Ltd. (1996), which is hereby incorporated herein by reference. However, controlling the animation of such animated facial gestures is cumbersome since each individual facial component has to be individually controlled at every instance in time.
In view of the foregoing, it is apparent that previously proposed techniques for providing a computer generated synthetic face do not provide certain features which would make the computer generated synthetic face more realistic. Also, the previously proposed techniques do not allow a computer generated synthetic face to be easily controlled. Accordingly, it would be desirable to provide a technique for providing a more realistic and easily controllable computer generated synthetic face.